Sega CD Transfer Suite

What It Does

This cable and the accompanying software allow you to do two things. The first is to test your programs on real Genesis/Sega CD hardware without burning a CD-R or using a Flash cartridge. The second is to dump Genesis and 32X cartridges to a file without the use of grey market hardware such as the Super Magic Drive or complicated traditional homebrew dumpers. This method is simple and inexpensive. If you can solder (and maybe even if you can't) you can make the cable needed for this setup.

How To Make The Cable

All you have to do is make a cable to connect your PC's Parallel port to your Genesis' 2nd Controller port. The only parts you need are two connectors and the wire to connect them; however, the easiest way to go about this is to start with a standard RS-232 serial cable but not a Null Modem cable and then make an adapter to connect it to your parallel port. The pinout is as follows:

Genesis (DB-9) Pin

PC (DB-25) Pin

1 (D0)

2 (D0)

2 (D1)

3 (D1)

3 (D2)

4 (D2)

4 (D3)

5 (D3)

5 (+5V)

Not Connected

6 (TL)

15 (Error)

7 (TH)

14 (Auto Line Feed)

8 (Ground)

21 (Ground) [pins 22-25 will also work]

9 (TR)

13 (Select) [optional]

How To Use The Software

Using the Boot Menu: Use the controller to move the arrow up and down. Press start to load a program (.bin files). Press 'A' to open a text file (.txt or .asm files).
Press 'B' to play a raw sound clip (.raw files). The last two are rather primitive and are there for demonstration purposes only (and to pad the ISO).

sendtest.exe/recvtest.bin:This a simple test program to make sure your cable is working properly. Start up the program on the Genesis/Sega CD first then load up the program on your PC. Once both are started, type in a message (without spaces) on your PC and hit enter. If everything is working as it should the message will display on your TV.

transfer.exe/transfer.bin:This is used to send your programs to the Genesis. Start the PC program first then start the Genesis/Sega CD program. Once both are started type in a file name and the address in memory you want it executed from. The file will then transfer and the Genesis 68K will do a jmp to the address specified.

dump.exe/dumpb.bin:This is used to dump cartridges. Before you can use this you need to put a piece of tape on the cartridge you want to dump. Put it on pin B32 (the pin furthest to the right on the front of the cartridge). This will keep the game from booting up and will instead cause the Sega CD to boot. Once this is done, start up dumpb.bin on the Genesis/Sega CD first and then dump.exe on your PC. You will then be presented with a few options on your Genesis as to the size of the cartridge. 'Auto' will use the size in the header of the cart, but since it's possible not all games will have a proper header you are also given choices as to the size of the cart in megabits. Choose one and press start. The transfer will begin and you'll get a progress indicator on your PC. The percentage is updated every 64KB (which takes about 5-6 seconds on my computer), so don't worry if it doesn't change immediately. Once the dump is complete you'll have a file called output.bin in the same folder as dump.exe

sendtest.bin:I never wrote a corresponding PC program for this, but I've put it here in case it's needed for debugging in the future.

Notes

The cable must be plugged into the player 2 port.
Having the cable plugged into the Genesis may cause interference on your TV.
The transfer program can only handle files that are 64KB or less in size.

Downloads

Here you can download all the files you need to get this working. Inside the zip you'll find an ISO file, three EXE files and a DLL file. Burn the ISO to a CD-R for use in your Sega/Mega CD.

New Version 1.1: Now supports dumping of 40Mb carts (Super Street Figher 2), the Sega/Mega CD BIOS, and SMS cartridges (requires adapter with pin B30 taped over or disconnected).
US Sega CD: comcable11.zip

Old Version 1:
Us Sega CD: comcable.zip
European Mega CD: comcableeu.zip (Thanks to Tom41 for the needed data)
Japanese Mega CD: comcablejap.zip (Thanks to whoever it was who sent me the data, I forget who it was)

Contact

If you have questions, comments, or a bug to report, you can reach me via e-mail (mask_of_destiny@hotmail.com), via aim (SN: chaostavi) or on one of the message boards I frequent.

Thanks

Thanks to Charles MacDonald for his excellent VDP and I/O documenation (http://cgfm2.emuviews.com/), to the guy who wrote inpout32.dll and to all the people mentioned on my Sega CD/SLO pages.